(CNN) -- Lawmakers are bracing for President Donald Trump's announcement on tariffs Thursday in part because most aren't sure what is coming.
The President is expected to unveil some kind of plan to slap new tariffs onto steel and aluminum Thursday at the White House, but aides and members on Capitol Hill lament they've been largely kept in the dark on the details of the plans, adding to anxieties that Trump could ignore their suggested changes and set in motion retaliation from US allies.
Over the last week, Republican lawmakers and aides have worked publicly and behind the scenes to tailor Trump's tariffs, convince him they could overshadow any economic benefits of the tax cuts they passed last year and try to find a way to convince the President to make them more targeted. But as of Thursday afternoon it was unclear whether their efforts had made an impact.
Sen. John Cornyn, the Senate's Majority Whip and second ranking Republican in the chamber, told reporters Thursday morning that he still had not been briefed on the White House's plans.
"My staff may have gotten a heads up but I have been distracted by other things. So, I have not gotten a briefing. So, I don't know what he's going to do," Cornyn said. "I think there has been a lot of feedback and the suggestion that if the President is going to proceed on this in a more targeted and surgical basis rather than across the board."
In recent days, Republicans have found themselves diametrically opposed to their President on the tariffs and trade, an issue as fundamental to the GOP's brand as tax cuts or the Second Amendment. And while lawmakers have bemoaned Trump's positions or style before, the latest episode reveals a real schism between the traditional Republican Party dogma and the populist brand of ideas Trump spent his campaign promoting.
"He feels like he's made campaign promises, and I think he wants to be able to deliver on that promise," Cornyn said.
In the wake of Gary Cohn's resignation, lawmakers have lost a key ally on trade in Trump's inner circle and there is growing frustration among congressional Republicans about where Trump is getting his advice. Senators complain that White House trade adviser Peter Navarro is counterproductive.
Sen. John Thune, a Republican member of leadership, accused Navarro of giving Trump "bad advice" on Wednesday.
Lawmakers have tried to convince Trump to at the very least to offer exceptions to some US allies like Mexico or Canada when he makes his announcement and are making the case that Trump needs to curtail the tariffs or he could risk undermining his own tax bill's impact on the economy. Senators continue to stay in contact with the White House in recent days even as frustration is mounting. On Tuesday, White House Chief of Staff John Kelly met with roughly half a dozen senators to hear them out on trade issues over breakfast and a source familiar to the situation told CNN that Ohio Sen. Rob Portman, a former US trade representative, talked with Robert Lighthizer, the current US trade representative, Wednesday night.
One GOP Senate aide told CNN that part of the problem for lawmakers in getting clarity is that the White House's plans are still very much in flux.
Multiple senior administration officials familiar with the Trump's plans said the President was slated to sign something Thursday afternoon -- but what exactly that would be remained a question since it's not clear that the actual tariff order would be completed and legally ready. CNN reported Thursday that one option is for the President to sign a memo or proclamation announcing his intent to take action on steel tariffs. Or he could sign a more substantial order if the vetting is completed. One official said Thursday morning "it looks like we will have the real deal."
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